Olympus Japan has details of the new firmware for the Olympus OM-D E-M5, which adds the following:
Small AF target (icon) was added to the AF target settings.
ISO LOW (100 equivalent) was expanded on the low sensitivity side.
The firmware on the Olympus OM-D E-M5 can be updated using the Olympus Digital Camera Updater software available from Olympus, with the camera connected to your computer via the USB cable. (via 43rumors).